Maintenance Matters

A clean plane is a safer plane and a source of pride.


Cleaning your plane seems like such a simple thing, but that doesn’t mean there aren’t right and wrong ways to do it. Major damage can result from improper cleaning, so let’s take a look at what works and what doesn’t when it comes to keeping your plane looking good.

Cleaning Windows and Windshields

The surfaces most often cleaned and most vulnerable to damage are acrylic windows and windshields. Just about every time you fly, you will have occasion to clean the windshield. Improper cleaning will reveal itself fairly quickly, but some mistakes may take longer to exact their toll. Window material may go by names such as Lucite or Plexiglas. No matter the name, almost all Experimental aircraft windows and windshields are made of acrylic, so be sure to only use cleaners and polishes approved for use on acrylic, not glass window cleaners.

Clean your acrylic windows with a product specifically made for the purpose such as Plexus. Use a clean cotton or microfiber cloth. An up-and-down motion is preferred over a circular motion. Remove watches, rings and other things that might scratch your windows.

The best thing to remove dust and loose material on a window is clean water. A gentle spray will wash away most dust and at least a few bugs. Even better is a gentle application of soapy water. Be sure to use gentle soap such as dish soap made for hand washing dishes (not dishwasher or most laundry soaps). Popular products like Dove or Ajax liquid dish soap work well, as does Woolite, a gentle laundry soap favored by the staff at our sister publication, Light Plane Maintenance (LPM). All of these should be well-diluted in clean water. Do not use any ammonia-based window cleaners like Windex or household cleaners like 409 or Simple Green. These contain chemicals that can damage acrylic.

Stubborn spots on acrylic surfaces need to be removed gently using your bare hand or nothing harsher than a soft cotton or microfiber cloth. In all cases it is imperative to only use clean implements to wash acrylic surfaces. The priority here is to avoid scratches. Paper towels should never be used on acrylic windows or windshields.

It is best to remove watches and rings before cleaning windows. Even belt buckles or pants rivets can cause trouble if you need to lean over the windshield to clean the opposite side. If this sounds extreme, remember how much work it was to install the windshield the first time. You don’t really want to do that again, do you?

If you encounter a really stubborn spot that has you thinking about reaching for the big guns, in other words strong solvents, take a breath first. The stronger the solvent the more likely it is to do permanent damage. Mineral spirits can be considered, but beyond that, solvents such as acetone or methyl ethyl ketone (MEK) are very likely to do more harm than good. If it comes to that, it will be better to leave a small spot that won’t yield to your efforts rather than create a larger spot that will permanently mar a window or windshield.

If you are somewhere where you do not have access to soapy water, I’ve had good luck cleaning windshields with a product called Plexus. It is specifically designed for cleaning acrylic windows. Spray it on generously and then wipe it off with a clean cotton or microfiber towel. After using the towel once, do not reuse it on a windshield until it has been washed. Wipe with an up-and-down motion, not a circular motion, for best results. Cee Bailey’s Premium Windshield Cleaner or Meguair’s PLASTX also work well. PLASTX is a cleaner and polish, so it is very good on tiny scratches or surfaces dulled by prolonged exposure to weather. Cee Bailey’s makes windshields for many motorcycles and a number of Experimental airplane kits including Glasair, Zenith and the RV-10. There may be other cleaners that work just as well, but you should always test any new product before you use it on your plane.

If You Scratch It

Scratches can often be removed successfully if they aren’t too deep and especially if they aren’t in a primary vision area. Aircraft Spruce and other aviation vendors sell kits that take you through several steps of using finer and finer abrasives before finally polishing the scratched spot until it is clear. You can duplicate the contents of the kit if you have a number of wet and dry sandpaper grades from 400 to 2000 grit and then use a polishing compound to finish. The kit is just more convenient for most people. The important thing is to remove the absolute minimum amount of material. If your view is distorted by the repair, you may have no choice but to replace the damaged window. This is one place where an ounce of scratch prevention is worth a pound of scratch removal cure, and then some.

If you do have Lexan (polycarbonate) windows, scratch removal is much more difficult because Lexan is so soft. A scratch-filling polish like Mequair’s PLASTX may help, but there are fewer good options than there are for acrylics.

Before You Wash Your Plane

Be sure not to run afoul of any local airport regulations regarding where you can wash your plane and what soaps you may use. Your airport manager should have this information readily available and may have a designated wash area that complies with environmental regulations.

It is a good idea to remove your watch, rings, belt buckles, or anything else that can scratch your plane before you wash it. If possible point your plane into the wind, chock the wheels, and install control locks. You don’t want thinks banging around or rolling off while you are trying to wash your plane. Protect static ports and the pitot tube inlet from wash water. Be sure to remove these covers after you wash.

Washing Your Plane

The best approach to washing a plane usually involves tackling tough spots first, and then washing the whole plane with soapy water, finishing with a rinse of clear water. For tough spots Extreme Simple Green Aircraft & Precision Cleaner seems to work the best. This should not be confused with the more common household version of Simple Green. Regular Simple Green is corrosive when used to clean aluminum. It can work into the joints between aircraft skins and do major damage over time. Do not use it on your plane.

Extreme Simple Green Aircraft & Precision Cleaner applied full strength is effective at removing bugs and other dirt from leading edges of wings and struts. It is not recommended for use on windshields or other acrylic windows unless diluted. Do not use regular household Simple Green.

To clean areas such as leading edges or aircraft bellies, spray on undiluted Aircraft Simple Green, let it soak for a minute or two, and then wipe it off. Most insects, grease, and exhaust stains will yield to this treatment after some wiping with a clean cloth. Repeat the process for really stubborn spots. It is best to avoid strong solvents, but if you must employ harsh means, be sure to test the product in a place where possible damage will not be readily visible. Varsol (aliphatic naptha) will work well on really stubborn grease and exhaust deposits on the belly, but it should be used sparingly and washed off after use. Mineral spirits may also do the trick and should not harm paint, but again, it will need to be washed off after use because it leaves a film. Avoid harsh solvents such as lacquer thinner, acetone, or MEK.

Use personal protective equipment, especially when using undiluted cleaning chemicals. Nitrile or dishwashing gloves are a good idea, as is eye protection. A clear full-face protector is a good idea when cleaning the belly of the airplane where chemicals and grease can easily drip into your eyes and face. An automotive-type creeper is also nice for rolling around under the wings and belly of the plane. You can pick these items up at Harbor Freight for very reasonable prices.

Once tough grime and bugs have been removed, wash the entire plane with soapy water, again using only mild soap as previously mentioned, or you can use Aircraft Simple Green diluted 10:1 with water. Undiluted Aircraft Simple Green should not be used on acrylic surfaces. Pressure washing is not recommended, especially high-pressure washers. They can drive water and cleaning chemicals into seams and joints in aircraft skins and penetrate seals into bearings and actuators. Even a garden hose with a spray nozzle should not be directed straight at bearings, rod ends, or hydraulic actuators. Avoid abrasive cleaners or strong alkali soaps.

An automotive-type creeper and a full face shield work best for cleaning the belly of your airplane.

After Washing

After your plane has been washed and rinsed, dry it thoroughly with a chamois or old, clean, bath towels. Use compressed air to blow out any trapped water, and be sure to remove any protection from the pitot tube and static ports. A squirt of WD-40 or other water-displacing lube can help flush water from exposed rod ends and hinges. Sump your fuel tanks to be sure no wash water got into the fuel system.

Use compressed air to blow wash water out of places where it might collect or be trapped after washing. Trapped water can contribute to corrosion.

Be sure to note any corrosion, loose or missing fasteners, peeling paint, or cracks you may have seen when washing or drying the plane. This is the best time to look for these things, since the plane will be clean and your attention will be focused on the entire exterior of the aircraft. Anything that needs immediate attention should get it as soon as possible. If you really want to do some good research on aircraft corrosion control, you might want to take a look at FAA advisory circular AC43-4A. It is numbingly long, but at least it is free on the web, and it has some good information in it.

Use a water-displacing lube to protect things like rod ends after washing. WD-40 or Boeshield T-9 are good choices for this.

Obviously this is the time to think about waxing your plane if you have the time. As an alternative, it is a good idea to wax the leading edges of the wings, struts, and tail surfaces to make insect removal easier. This minimal application of carnauba-type wax will not take too much time and will make cleaning easier next time. Waxes that contain silicone should generally be avoided, especially if you have a fabric covered airplane. The silicone gets into the fabric and makes it all but impossible to patch it later should the need arise.

If you intend to wax your whole plane, or if you have oxidized paint that needs to be polished out, you will want to invest in a power buffer/polisher. This is where I get on the phone and call the local aircraft detailer, but you can do it yourself if you have the time and energy. Just be sure to get some knowledgeable help the first time you do. This is especially true for those of you with unpainted aluminum wings, which is really a subject of its own. Polished aluminum can be a beautiful thing, but there are definitely easier and harder ways to do it. Actually, there are just hard and harder ways to do it if we are being perfectly honest. Talk to someone with firsthand experience to get some helpful hints.

Besides having a nice clean plane, there is a real benefit to washing your plane. It gives you the chance to spot corrosion and minor cracking that may have escaped your notice on your typical preflight inspection. Be on the lookout for these things as you give your prized bird the once over.

Dave Prizio is a Southern California native who has been plying the skies of the L.A. basin and beyond since 1973. Born into a family of builders, it was only natural that he would make his living as a contractor and spend his leisure time building airplanes. He has so far completed three—a GlaStar, a Glasair Sportsman, and a Texas Sport Cub—and he is helping a friend build a fourth, an RV-8. When he isn’t building something, he likes to share his love of aviation with others by flying Young Eagles or volunteering as an EAA Technical Counselor. He is also a member of the EAA Homebuilt Aircraft Council.

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Dave Prizio
Dave Prizio has been plying the skies of the L.A. basin and beyond since 1973. Born into a family of builders, it was only natural that he would make his living as a contractor and spend his leisure time building airplanes. He has so far completed four—two GlaStars, a Glasair Sportsman, and a Texas Sport Cub—and is helping a friend build an RV-8. When he isn’t building something, he shares his love of aviation with others by flying Young Eagles or volunteering as an EAA Technical Counselor. He is also an A&P mechanic, Designated Airworthiness Representative (DAR), and was a member of the EAA Homebuilt Aircraft Council for six years.


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